Since the International Energy Agency seems intelligent to me, I’ll just quote their executive summary. If you’re too busy for even the executive summary, let me summarize the summary:

Given the actions that countries are now planning, we could have an increase of around 2.6 °C over preindustrial temperature by 2100, and more after that.

Executive summary

A major milestone in efforts to combat climate change is fast approaching. The importance of the 21st Conference of the Parties (COP21) – to be held in Paris in December 2015 – rests not only in its specific achievements by way of new contributions, but also in the direction it sets. There are already some encouraging signs with a historic joint announcement by the United States and China on climate change, and climate pledges for COP21 being submitted by a diverse range of countries and in development in many others. The overall test of success for COP21 will be the conviction it conveys that governments are determined to act to the full extent necessary to achieve the goal they have already set to keep the rise in global average temperatures below 2 degrees Celsius (°C), relative to pre-industrial levels.

Energy will be at the core of the discussion. Energy production and use account for two-thirds of the world’s greenhouse-gas (GHG) emissions, meaning that the pledges made at COP21 must bring deep cuts in these emissions, while yet sustaining the growth of the world economy, boosting energy security around the world and bringing modern energy to the billions who lack it today. The agreement reached at COP21 must be comprehensive geographically, which means it must be equitable, reflecting both national responsibilities and prevailing circumstances. The importance of the energy component is why this World Energy Outlook Special Report presents detailed energy and climate analysis for the sector and recommends four key pillars on which COP21 can build success.

Energy and emissions: moving apart?

The use of low-carbon energy sources is expanding rapidly, and there are signs that growth in the global economy and energy-related emissions may be starting to decouple. The global economy grew by around 3% in 2014 but energy-related carbon dioxide (CO2) emissions stayed flat, the first time in at least 40 years that such an outcome has occurred outside economic crisis.

Renewables accounted for nearly half of all new power generation capacity in 2014, led by growth in China, the United States, Japan and Germany, with investment remaining strong (at $270 billion) and costs continuing to fall. The energy intensity of the global economy dropped by 2.3% in 2014, more than double the average rate of fall over the last decade, a result stemming from improved energy efficiency and structural changes in some economies, such as China.

Around 11% of global energy-related CO2 emissions arise in areas that operate a carbon market (where the average price is $7 per tonne of CO2), while 13% of energy-related CO2 emissions arise in markets with fossil-fuel consumption subsidies (an incentive equivalent to $115 per tonne of CO2, on average). There are some encouraging signs on both fronts, with reform in sight for the European Union’s Emissions Trading Scheme and countries including India, Indonesia, Malaysia and Thailand taking the opportunity of lower oil prices to diminish fossil-fuel subsidies, cutting the incentive for wasteful consumption.

The energy contribution to COP21

Nationally determined pledges are the foundation of COP21. Intended Nationally
Determined Contributions (INDCs) submitted by countries in advance of COP21 may vary in scope but will contain, implicitly or explicitly, commitments relating to the energy sector. As of 14 May 2015, countries accounting for 34% of energy-related emissions had submitted their new pledges.

A first assessment of the impact of these INDCs and related policy statements (such as by China) on future energy trends is presented in this report in an “INDC Scenario”. This shows, for example, that the United States’ pledge to cut net greenhouse-gas emissions by 26% to 28% by 2025 (relative to 2005 levels) would deliver a major reduction in emissions while the economy grows by more than one-third over current levels. The European Union’s pledge to cut GHG emissions by at least 40% by 2030 (relative to 1990 levels) would see energy-related CO2 emissions decline at nearly twice the rate achieved since 2000, making it one of the world’s least carbon-intensive energy economies. Russia’s energy-related emissions decline slightly from 2013 to 2030 and it meets its 2030 target comfortably, while implementation of Mexico’s pledge would see its energy-related emissions increase slightly while its economy grows much more rapidly. China has yet to submit its INDC, but has stated an intention to achieve a peak in its CO2 emissions around 2030 (if not earlier), an important change in direction, given the pace at which they have grown on average since 2000.

Growth in global energy-related GHG emissions slows but there is no peak by 2030 in the INDC Scenario. The link between global economic output and energy-related GHG emissions weakens significantly, but is not broken: the economy grows by 88% from 2013 to 2030 and energy-related CO2 emissions by 8% (reaching 34.8 gigatonnes). Renewables become the leading source of electricity by 2030, as average annual investment in nonhydro renewables is 80% higher than levels seen since 2000, but inefficient coal-fired power generation capacity declines only slightly.

With INDCs submitted so far, and the planned energy policies in countries that have yet to submit, the world’s estimated remaining carbon budget consistent with a 50% chance of keeping the rise in temperature below 2 °C is consumed by around 2040—eight months later than is projected in the absence of INDCs. This underlines the need for all countries to submit ambitious INDCs for COP21 and for these INDCs to be recognised as a basis upon which to build stronger future action, including from opportunities for collaborative/co-ordinated action or those enabled by a transfer of resources (such as technology and finance). If stronger action is not forthcoming after 2030, the path in the INDC Scenario would be consistent with an an average temperature increase of around 2.6 °C by 2100 and 3.5 °C after 2200.

What does the energy sector need from COP21?

National pledges submitted for COP21 need to form the basis for a “virtuous circle” of rising ambition. From COP21, the energy sector needs to see a projection from political leaders at the highest level of clarity of purpose and certainty of action, creating a clear expectation of global and national low-carbon development. Four pillars can support that achievement:

1. Peak in emissions – set the conditions which will achieve an early peak in global
energy-related emissions.

3. Lock in the vision – translate the established climate goal into a collective long-term emissions goal, with shorter-term commitments that are consistent with the long-term vision.

4. Track the transition – establish an effective process for tracking achievements in
the energy sector.

Peak in emissions

The IEA proposes a bridging strategy that could deliver a peak in global energy-related
emissions by 2020. A commitment to target such a near-term peak would send a clear message of political determination to stay below the 2 °C climate limit. The peak can be
achieved relying solely on proven technologies and policies, without changing the economic and development prospects of any region, and is presented in a “Bridge Scenario”. The technologies and policies reflected in the Bridge Scenario are essential to secure the long-term decarbonisation of the energy sector and their near-term adoption can help keep the door to the 2 °C goal open. For countries that have submitted their INDCs, the proposed strategy identifies possible areas for over-achievement. For those that have yet to make a submission, it sets out a pragmatic baseline for ambition.

• Progressively reducing the use of the least-efficient coal-fired power plants and
banning their construction.

• Increasing investment in renewable energy technologies in the power sector from
$270 billion in 2014 to $400 billion in 2030.

• Gradual phasing out of fossil-fuel subsidies to end-users by 2030.

• Reducing methane emissions in oil and gas production.

These measures have profound implications for the global energy mix, putting a brake on growth in oil and coal use within the next five years and further boosting renewables. In the Bridge Scenario, coal use peaks before 2020 and then declines while oil demand rises to 2020 and then plateaus. Total energy-related GHG emissions peak around 2020. Both the energy intensity of the global economy and the carbon intensity of power generation improve by 40% by 2030. China decouples its economic expansion from emissions growth by around 2020, much earlier than otherwise expected, mainly through improving the energy efficiency of industrial motors and the buildings sector, including through standards for appliances and lighting. In countries where emissions are already in decline today, the decoupling of economic growth and emissions is significantly accelerated; compared with recent years, the pace of this decoupling is almost 30% faster in the European Union (due to improved energy efficiency) and in the United States (where renewables contribute one-third of the achieved emissions savings in 2030). In other regions, the link between economic growth and emissions growth is weakened significantly, but the relative importance of different measures varies. India utilises energy more efficiently, helping it
to reach its energy sector targets and moderate emissions growth, while the reduction of
methane releases from oil and gas production and reforming fossil-fuel subsidies (while
providing targeted support for the poorest) are key measures in the Middle East and Africa, and a portfolio of options helps reduce emissions in Southeast Asia. While universal access to modern energy is not achieved in the Bridge Scenario, the efforts to reduce energy related emissions do go hand-in-hand with delivering access to electricity to 1.7 billion people and access to clean cookstoves to 1.6 billion people by 2030.

I’m not as knowledgeable about this as I should be. But here’s one thing: “just a matter of time” is not good enough; we’re in a race against time. The latest IPCC report shows that if we don’t cease carbon emissions by 2040, we’ll have to go carbon negative later this century to keep a good chance of staying below 2°C warming. See the graphs and discussion here:

(For a graphic example that needs no statistics, here’s a 1200y old temple which due to a miracle improbability did not get razed away by the rolling stones during the Great Uttarakhand Washout 2013: https://www.google.fi/search?site=imghp&tbm=isch&q=shiva+temple+flood
For another 2013 example close to my home, look up the Danube floodmarks on a 500y+ old building in Passau, Germany.)

But that was yesterday. Check out the (First?) Great Texan Flooding of 2015. Here the statistics is broken (suggesting a critical system transition), giving recurrence times between 5000y and 100000y, i.e. beyond the entire Holocene. See comments here: http://neven1.typepad.com/blog/2015/06/what-its-all-about.html

Now I stop commenting for a while, so y’all don’t see my ugly avatar head too often :-) Flori aka Martin Gisser

What year are the 2.0 C, 2.6 C and 3.5 C increases measured from ? You mention pre-industrial levels, but what year marks the divide between pre- and post-industrial times ? I have heard a variety of dates mentioned, from 1750 to 1960, and I would expect a rise in temperature from 1750 to have much less effect than the same rise from 1960, for example.

If we are to set targets, then everybody needs to know precisely when that target is measured from, so that we can determine (or, at least, project) when that target is likely to be reached.

Of course, I appreciate that oceanic and solar cycles are trending (or appear about to trend) downwards, so the natural warming rate in the future may be less than it has been in the past few decades.

We are dealing with fuzzy exponential trends, so we don’t have those easy “precise targets” as in the statistics of a linear world. The question then is the order of magnitude, like: catastrophe vs.apocalypse. There is no exact target that separates one from the other. It could be 1.5°C or it could be 3°C. Plus (actually a multiplication) there’s the human co-factor, esp. the population-agriculture madness, resource depletion, war, etc.

Still the message of climate science is utterly crystal clear and unequivocal: Get off fossil carbon as quick and as soon as possible. No bickering about precise targets necessary.

Well, that makes it difficult to compare natural increases with anthropogenic increases. However, let’s say that all of the increase since global temperatures have been recorded has been anthropogenic. That would be :-

BEST global land +0.41 C per century since 1753
HadCRUT4 +0.48 C per century since 1850
NASA GISS +0.68 C per century since 1880
NOAA NCDC +0.69 C per century since 1880

Based on these rates of increase in global temperatures (which have included warming, cooling and stasis periods) why do you say “Still the message of climate science is utterly crystal clear and unequivocal: Get off fossil carbon as quick and as soon as possible. No bickering about precise targets necessary.” ?

“Rate of increase since 1880”?
Look at the Global Land-Ocean Temperature Index chart shown below: If you want a number that makes sense, start at 1970 to get the current rate of increase. That’s when we left the vagaries of natural variation and measurement error (cf. green error bar) and when the rising anthropogenic CO2 load started making a clear difference. All you need is a print-out and a ruler. No math needed beyond quotients. (A nice visual exercise every sceptic should do first: It also shows that the “hiatus” myth always was statistical nonsense.)

Sorry, I don’t see why you say that we have to start at 1970 to get a number that makes sense. Yes, the error bars are smaller in about 2008 than they are in about 1948. How do you deduce from that that the rising anthropogenic CO2 load started making a clear difference in 1970 ?

Yes, the current warming started in 1964, but why don’t you say that the rising anthropogenic CO2 load started making a clear difference in 1910, which was also (as in 1964) when the end of a cooling period was followed by the start of a warming period ? How do you attribute the warming since 1970 (+0.04 to +0.68 =+0.64 C in 44 years) to CO2, and not the warming (from -0.46 to +0.14 = +0.60 C in 34 years) from 1910 to 1944 ?

I think that we need more error bars on the graph before we can make a claim that one warming period was due to the rising anthropogenic CO2 load, and the other was not. Even then, the ‘real’ temperature at the start or at the end of a warming period may be higher or lower than the data point.

(The current warming neither “started in 1964” nor “started in 1970”: Both is statistical nonsense, just like “stopped 1998” was.)

For an unbiased look at the data (without theory) it is obviously least erroneous to start around 1970 to get the current trend. Just minimize and homogenize the noise around the trendline (using eyballs and transparent ruler — and don’t get distracted by the red curve). In engineering there’s the adage: “Keep it simple, but not too simple”.

For more interpretation of data, you need some theory behind the data.

The only theory we have here is Fourier’s old greenhouse theory 1824. (Backed up with Tyndall’s identification of the main greenhouse gases 1862, Arrhenius’ logarithmic formula 1896 and the Keeling curve.) Since the Keeling curve looks exponential, a linear trend is to be expected as a first unbiased estimation of things. 1970 was 330ppm, today is 400ppm, Holocene was 280ppm. Thus theory confirms my first zero-theory Bayesian approach to start at 1970.

As far as I can tell, the IPCC does not give a precise definition of “pre-industrial temperature levels”. I asked a guru of mine, and he said:

There is no universal standard definition of “pre-industrial”. I see 1850 and 1880 often used (depending on which data set people like; they don’t all go back to 1850). Sometimes modelers use 1800 or even earlier, on the grounds that they don’t want any industrial forcing. Observational people accept a little bit of fossil emissions before their “pre-industrial” date just because their records don’t go earlier, so “pre-industrial” is more like “whenever our data set starts”.

If we use 1880 as our starting point, since that’s the starting-point for GISS:

(click for details), then we have already experienced a warming of roughly 0.8 °C, so we have 1.2 ° C more to go before we reach 2 ° C warming. This rough figure seems widely accepted, though sometimes I see people say we’ve experienced 1 ° C over pre-industrial levels.

As Florifulgurator pointed out, there’s no sharp borderline between problem and disaster, so a bit of fuzziness here is not fatal, though it annoys my sensibilities.

Yes, it annoys my sensibilities also :-) However, I have replied to ‘Florifulgurator’ with the trends in various global temperature records, since it is the rate of increase that’s important, and we have so far had 0.41 C to 0.69 C per century of warming in the various global records. Obviously, if we are using 2.0 C as some sort of ‘tipping point’ then we have about 3-5 centuries from the start point before we reach that.

Richard, your “obvious” conclusion appears to be based on an assumption that the relevant rate of temperature increase a) has been, b) will continue to be in the range 0.41 to 0.69 C per century. If so, that tees up the question: Why do you think b) is obvious?

that it is reasonable to assume that future trends will be close to that range, so that we will then have about 3-5 centuries from the start point to reach the two degrees target.

Some alarmists have said that the two degrees target will be reached within this century, which would require a much greater rate of global temperature increase, over a sustained period of time, than we have ever experienced before, which seems highly improbable, especially at a time when solar and oceanic cycles are at, or just past, their maximum points.

Sounds great as long as China is able to maintain internal political stability, the US avoids a debt crisis, and the costs of extracting fossil fuels and creating renewables stay constant. If China’s central government fails, if the US dollar is no longer the world reserve currency, and if resource depletion requires use of resources where the energy required for extraction and processing goes up sharply, these “ambitions” may be frustrated.

JUDITH SWALES, FONTERRA AUSTRALIA: This year, around 65 billion litres of milk will be traded on the global dairy trade. By 2023, we’re anticipating around 900 billion litres of milk. So you look at that growth and you go, “Well, that’s astronomical.”

The Chinese had always shunned milk products, and indeed many lack some genes for metabolizing lactose, since they didn’t coevolve with cattle the way people from the Middle East did. It’s sad that they’re taking to milk and beef now.

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